After the water-to-wine miracle, Jesus went to Jerusalem. In the temple, he saw businessman selling stuff. But Jesus seemed to interrupt the scene big time. The image of seeming peaceful business to chaos that seems to be instigated by Jesus seems strange, but it is important to discuss.
The first thing that we'll discuss is Jesus's quote regarding the events. Jesus rebuked the sellers and said that he does not want the house of the Father to be "a house of merchandise." (2:16) The point of the temple is for people to dedicate time with God; business is not meant to be there. Jesus wanted to ensure that people can worship distraction-free, so his anger does have justification. In fact, the writers at Ligonier noted that the temple business is kinda corrupt (since the poor may have to pay up a lot).
It's also worth noting that since the Temple is a place of God, Jesus (since He is God) has authority there. In fact, the disciples knew from prior Scripture that God cares about His temple (2:17). A whip is commonly used as a symbol for authority and defense, much like a gun for policemen, so there's no saying that violence must have been used. It's possible that the money is poured into storage area since temples have been used for storage (though the banking and business have to be done outside the temple area or even moved away altogether). Overturning tables could also be done for cleanup -- not to mention that cleanup itself subverts the business of doves there. Though it's worth noting that the cleanup itself is meant to be a rapid thing (so God activities can continue as normal).
If the temple cleaning still seems confusing, think of it as a librarian doing a normal business when some people bring a loudspeaker and started to play jamming music. Jamming music is a normal activity in parties, but not in a library, where the point is for people to be able to read and study without much distractions. Since the librarian manages the library, it's reasonable for the library to be angry at the situation and tell the music players to shut down (or even unplug the speaker when they don't seem to listen).